From: Jens Axboe <axboe@suse.de>
To: Andrew Morton <akpm@digeo.com>
Cc: lkml <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: 2.5.38-mm2
Date: Mon, 23 Sep 2002 09:16:33 +0200 [thread overview]
Message-ID: <20020923071633.GA15479@suse.de> (raw)
In-Reply-To: <3D8E96AA.C2FA7D8@digeo.com>
On Sun, Sep 22 2002, Andrew Morton wrote:
> +read-latency.patch
>
> Fix the writer-starves-reader elevator problem. This is basically
> the read_latency2 patch from -ac kernels.
>
> On IDE it provides a 100x improvement in read throughput when there
> is heavy writeback happening. 40x on SCSI. You need to disable
Ah interesting. I do still think that it is worth to investigate _why_
both elevator_linus and deadline does not prevent the read starvation.
The read-latency is a hack, not a solution imo.
> tagged command queueing on scsi - it appears to be quite stupidly
> implemented.
Ahem I think you are being excessively harsh, or maybe passing judgement
on something you haven't even looked at. Did you consider that you
_drive_ may be the broken component? Excessive turn-around times for
request when using deep tcq is not unusual, by far.
--
Jens Axboe
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next prev parent reply other threads:[~2002-09-23 7:16 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-23 4:20 2.5.38-mm2 Andrew Morton
2002-09-23 7:16 ` Jens Axboe [this message]
2002-09-23 7:43 ` 2.5.38-mm2 Andrew Morton
2002-09-24 21:10 ` 2.5.38-mm2 Bill Davidsen
2002-09-23 9:45 ` 2.5.38-mm2 [PATCH] Dipankar Sarma
2002-09-23 16:28 ` Andrew Morton
2002-09-23 17:33 ` Dipankar Sarma
2002-09-24 4:41 ` Rusty Russell
2002-09-24 10:24 ` Dipankar Sarma
2002-09-24 14:56 ` Rusty Russell
2002-09-23 9:56 ` 2.5.38-mm2 [PATCH] (dcache) Dipankar Sarma
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